title: Healthcare utilization and cost of pneumococcal disease in the United States.
abstract: BACKGROUND
  Streptococcus pneumoniae continues to cause a variety of common clinical syndromes, despite vaccination programs for both adults and children. The total U.S. burden of pneumococcal disease is unknown.
  
  
  METHODS
  We constructed a decision tree-based model to estimate U.S. healthcare utilization and costs of pneumococcal disease in 2004. Data were obtained from the 2004-2005 National (Hospital) Ambulatory Medical Care Surveys (outpatient visits, antibiotics) and the National Hospital Discharge Survey (hospitalization rates), and CDC surveillance data. Other assumptions regarding the incidence of each syndrome due to pneumococcus, expected health outcomes, and healthcare utilization were derived from literature and expert opinion. Healthcare and time costs used 2007 dollars.
  
  
  RESULTS
  We estimate that, in 2004, pneumococcal disease caused 4.0 million illness episodes, 22,000 deaths, 445,000 hospitalizations, 774,000 emergency department visits, 5.0 million outpatient visits, and 4.1 million outpatient antibiotic prescriptions. Direct medical costs totaled $3.5 billion. Pneumonia (866,000 cases) accounted for 22% of all cases and 72% of pneumococcal costs. In contrast, acute otitis media and sinusitis (1.5 million cases each) comprised 75% of cases but only 16% of direct medical costs. Patients ≥ 65 years old, accounted for most serious cases and the majority of direct medical costs ($1.8 billion in healthcare costs annually). In this age group, pneumonia caused 242,000 hospitalizations, 1.4 million hospital days, 194,000 emergency department visits, 374,000 outpatient visits, and 16,000 deaths. However, if work loss and productivity are considered, the cost of pneumococcal disease among younger working adults (18-<50) nearly equaled those ≥ 65.
  
  
  CONCLUSIONS
  Pneumococcal disease remains a substantial cause of morbidity and mortality even in the era of routine pediatric and adult vaccination. Continued efforts are warranted to reduce serious pneumococcal disease, especially adult pneumonia.
authors.affiliation: Division of Infectious Diseases and Health Policy Research Institute, University California Irvine School of Medicine, 100 Theory Ave, Suite 110, Irvine, CA 92697, USA. susan.huang@uci.edu
authors.forename: Susan S
authors.initials: SS
authors.lastname: Huang
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Johnson
authors.forename: G Thomas
authors.initials: GT
authors.lastname: Ray
authors.forename: Peter
authors.initials: P
authors.lastname: Wroe
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Lieu
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Moore
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Zell
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Linder
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Grijalva
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Metlay
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Finkelstein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003695:Delivery of Health Care / Q000191:economics* / Q000706:statistics & numerical data; D017048:Health Care Costs; D006801:Humans; D007223:Infant; D007297:Inpatients / Q000706:statistics & numerical data; D008875:Middle Aged; D018803:Models, Economic; D010033:Otitis Media / Q000191:economics / Q000453:epidemiology; D010045:Outpatients / Q000706:statistics & numerical data; D011008:Pneumococcal Infections / Q000191:economics* / Q000453:epidemiology; D018805:Sepsis / Q000191:economics / Q000453:epidemiology; D012852:Sinusitis / Q000191:economics / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D055815:Young Adult